Implicit Differentiation
1. **State the problem:** Differentiate the implicit equation $$7y^2 + \sin(3x) = 12 - \frac{y}{4}$$ with respect to $$x$$.
2. **Rewrite the equation:** $$7y^2 + \sin(3x) = 12 - \frac{y}{4}$$.
3. **Differentiate both sides using implicit differentiation:**
- Derivative of $$7y^2$$: $$7 \cdot 2y \cdot \frac{dy}{dx} = 14y \frac{dy}{dx}$$ by the chain rule.
- Derivative of $$\sin(3x)$$: $$\cos(3x) \cdot 3 = 3 \cos(3x)$$ by the chain rule.
- Derivative of constant 12: $$0$$.
- Derivative of $$-\frac{y}{4}$$: $$-\frac{1}{4} \frac{dy}{dx}$$.
4. **Write the differentiated equation:**
$$14y \frac{dy}{dx} + 3 \cos(3x) = - \frac{1}{4} \frac{dy}{dx}$$.
5. **Group terms with $$\frac{dy}{dx}$$ on the left:**
$$14y \frac{dy}{dx} + \frac{1}{4} \frac{dy}{dx} = -3 \cos(3x)$$.
6. **Factor $$\frac{dy}{dx}$$:**
$$\left(14y + \frac{1}{4}\right) \frac{dy}{dx} = -3 \cos(3x)$$.
7. **Solve for $$\frac{dy}{dx}$$:**
$$\frac{dy}{dx} = \frac{-3 \cos(3x)}{14y + \frac{1}{4}} = \frac{-3 \cos(3x)}{14y + 0.25}$$.
8. **Final boxed answer:**
$$\boxed{\frac{dy}{dx} = \frac{-3 \cos(3x)}{14y + \frac{1}{4}}}$$